/*                        C G A R B S . C
 * BRL-CAD
 *
 * Copyright (c) 1990-2025 United States Government as represented by
 * the U.S. Army Research Laboratory.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public License
 * version 2.1 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this file; see the file named COPYING for more
 * information.
 */
/** @file vdeck/cgarbs.c
 *
 *  Routines to take a generalized ARB in 8-point form,
 *  determine which points are equivalent,
 *  decide which GIFT special-case solid fits this case,
 *  and convert the point list into GIFT format.
 *
 *  Author -
 *	Keith Applin
 *
 */

#include "common.h"

#include <stdio.h>
#include <math.h>
#include "vmath.h"
#include "raytrace.h"
#include "rt/geom.h"

#define YES	1
#define NO	0

/*
 *  Determines COMGEOM arb type of a general arb.
 *
 *  Returns -
 *	> 0	number of unique points, and updated *cgtype
 *	  0	error
 */
int
cgarbs(int *cgtype,
       const struct rt_arb_internal *gp,
       int uniq[8],           /* array of unique pt subscripts */
       int svec[11],          /* array of like pt subscripts */
       const double dist_tol  /* distance tolerance */
       )
{
    int	i, j;
    int	numuniq, unique, done;
    int	si;

    done = NO;		/* done checking for like vectors */

    svec[0] = svec[1] = 0;
    si = 2;

    for (i = 0; i < 7; i++) {
	unique = YES;
	if (done == NO)
	    svec[si] = i;
	for (j = i + 1; j < 8; j++) {
	    if (VNEAR_EQUAL(gp->pt[i], gp->pt[j], dist_tol))  {
		if (done == NO) svec[++si] = j;
		unique = NO;
	    }
	}
	if (unique == NO) {
	    /* point i not unique */
	    if (si > 2 && si < 6) {
		svec[0] = si - 1;
		if (si == 5 && svec[5] >= 6)
		    done = YES;
		si = 6;
	    }
	    if (si > 6) {
		svec[1] = si - 5;
		done = YES;
	    }
	}
    }
    if (si > 2 && si < 6)
	svec[0] = si - 1;
    if (si > 6)
	svec[1] = si - 5;
    for (i = 1; i <= svec[1]; i++)
	svec[svec[0]+1+i] = svec[5+i];
    for (i = svec[0]+svec[1]+2; i < 11; i++)
	svec[i] = -1;

    /* find the unique points */
    numuniq = 0;
    for (j = 0; j < 8; j++) {
	unique = YES;
	for (i = 2; i < svec[0]+svec[1]+2; i++) {
	    if (j == svec[i]) {
		unique = NO;
		break;
	    }
	}
	if (unique == YES)
	    uniq[numuniq++] = j;
    }

    /* put comgeom solid type into s_cgtype */
    switch (numuniq) {
	case 8:
	    *cgtype = 8;  /* ARB8 */
	    break;
	case 6:
	    *cgtype = 7;	/* ARB7 */
	    break;
	case 4:
	    if (svec[0] == 2)
		*cgtype = 6;	/* ARB6 */
	    else
		*cgtype = 5;	/* ARB5 */
	    break;
	case 2:
	    *cgtype = 4;	/* ARB4 */
	    break;
	default:
	    (void) fprintf(stderr,
			    "cgarbs: bad number of unique vectors (%d)\n",
			    numuniq);
	    return 0;
    }
    return numuniq;
}

/*
 *  Permute the points as directed.
 */
static void
arb_mv(point_t pts[8],
       const struct rt_arb_internal *gp,
       const int p0,
       const int p1,
       const int p2,
       const int p3,
       const int p4,
       const int p5,
       const int p6,
       const int p7
       )
{
    RT_ARB_CK_MAGIC(gp);
    VMOVE(pts[0], gp->pt[p0]);
    VMOVE(pts[1], gp->pt[p1]);
    VMOVE(pts[2], gp->pt[p2]);
    VMOVE(pts[3], gp->pt[p3]);
    VMOVE(pts[4], gp->pt[p4]);
    VMOVE(pts[5], gp->pt[p5]);
    VMOVE(pts[6], gp->pt[p6]);
    VMOVE(pts[7], gp->pt[p7]);
}

/*
 *  Rearranges arbs to be GIFT compatible
 *  The input in "gp" is not modified.
 *  The first "numvec" entries of "pts" are the GIFT format of arb "cgtype".
 *
 *  Returns -
 *	1	OK
 *	0	error
 */
int
redoarb(point_t pts[8],
	const struct rt_arb_internal *gp,
	int uniq[8],
	int svec[11],
	const int numvec,
	const int cgtype
    )
{
    int	i, j;
    int	prod;

    /* For all the cases that don't require shuffling, duplicate first */
    for (i = 0; i < 8; i++)  {
	VMOVE(pts[i], gp->pt[i]);
    }

    /* cgtype indicates which kind of ARB it is */
    switch (cgtype) {
	case 8:
	    break;

	case 7:
	    /* arb7 vectors: 0 1 2 3 4 5 6 4 */
	    switch (svec[2]) {
		case 0:			/* 0 = 1, 3, or 4 */
		    if (svec[3] == 1)	arb_mv(pts, gp, 4, 7, 6, 5, 1, 4, 3, 1);
		    if (svec[3] == 3)	arb_mv(pts, gp, 4, 5, 6, 7, 0, 1, 2, 0);
		    if (svec[3] == 4)	arb_mv(pts, gp, 1, 2, 6, 5, 0, 3, 7, 0);
		    break;
		case 1:			/* 1 = 2 or 5 */
		    if (svec[3] == 2)	arb_mv(pts, gp, 0, 4, 7, 3, 1, 5, 6, 1);
		    if (svec[3] == 5)	arb_mv(pts, gp, 0, 3, 7, 4, 1, 2, 6, 1);
		    break;
		case 2:			/* 2 = 3 or 6 */
		    if (svec[3] == 3)	arb_mv(pts, gp, 6, 5, 4, 7, 2, 1, 0, 2);
		    if (svec[3] == 6)	arb_mv(pts, gp, 3, 0, 4, 7, 2, 1, 5, 2);
		    break;
		case 3:			/* 3 = 7 */
		    arb_mv(pts, gp, 2, 1, 5, 6, 3, 0, 4, 3);
		    break;
		case 4:			/* 4 = 5 */
		    /* if 4 = 7  do nothing */
		    if (svec[3] == 5)	arb_mv(pts, gp, 1, 2, 3, 0, 5, 6, 7, 5);
		    break;
		case 5:			/* 5 = 6 */
		    arb_mv(pts, gp, 2, 3, 0, 1, 6, 7, 4, 6);
		    break;
		case 6:			/* 6 = 7 */
		    arb_mv(pts, gp, 3, 0, 1, 2, 7, 4, 5, 7);
		    break;
		default:
		    (void) fprintf(stderr, "redoarb: bad arb7\n");
		    return 0;
	    }
	    break;
	    /* end of ARB7 case */
	case 6:
	    /* arb6 vectors:  0 1 2 3 4 4 6 6 */
	    prod = 1;
	    for (i = 0; i < numvec; i++)
		prod = prod * (uniq[i] + 1);
	    switch (prod) {
		case 24:	/* 0123 unique */
		    /* 4=7 and 5=6  OR  4=5 and 6=7 */
		    if (svec[3] == 7)	arb_mv(pts, gp, 3, 0, 1, 2, 4, 4, 5, 5);
		    else	arb_mv(pts, gp, 0, 1, 2, 3, 4, 4, 6, 6);
		    break;
		case 1680:	/* 4567 unique */
		    /* 0=3 and 1=2  OR  0=1 and 2=3 */
		    if (svec[3] == 3)	arb_mv(pts, gp, 7, 4, 5, 6, 0, 0, 1, 1);
		    else	arb_mv(pts, gp, 4, 5, 6, 7, 0, 0, 2, 2);
		    break;
		case 160:	/* 0473 unique */
		    /* 1=2 and 5=6  OR  1=5 and 2=6 */
		    if (svec[3] == 2)	arb_mv(pts, gp, 0, 3, 7, 4, 1, 1, 5, 5);
		    else	arb_mv(pts, gp, 4, 0, 3, 7, 1, 1, 2, 2);
		    break;
		case 672:	/* 3267 unique */
		    /* 0=1 and 4=5  OR  0=4 and 1=5 */
		    if (svec[3] == 1)	arb_mv(pts, gp, 3, 2, 6, 7, 0, 0, 4, 4);
		    else	arb_mv(pts, gp, 7, 3, 2, 6, 0, 0, 1, 1);
		    break;
		case 252:	/* 1256 unique */
		    /* 0=3 and 4=7  OR 0=4 and 3=7 */
		    if (svec[3] == 3)	arb_mv(pts, gp, 1, 2, 6, 5, 0, 0, 4, 4);
		    else	arb_mv(pts, gp, 5, 1, 2, 6, 0, 0, 3, 3);
		    break;
		case 60:	/* 0154 unique */
		    /* 2=3 and 6=7  OR  2=6 and 3=7 */
		    if (svec[3] == 3)	arb_mv(pts, gp, 0, 1, 5, 4, 2, 2, 6, 6);
		    else	arb_mv(pts, gp, 5, 1, 0, 4, 2, 2, 3, 3);
		    break;
		default:
		    (void) fprintf(stderr, "redoarb: bad arb6\n");
		    return 0;
	    }
	    break;
	    /* end of ARB6 case */
	case 5:
	    /* arb5 vectors:  0 1 2 3 4 4 4 4 */
	    prod = 1;
	    for (i = 2; i < 6; i++)
		prod = prod * (svec[i] + 1);
	    switch (prod) {
		case 24:	/* 0=1=2=3 */
		    arb_mv(pts, gp, 4, 5, 6, 7, 0, 0, 0, 0);
		    break;
		case 1680:	/* 4=5=6=7 */
		    /* do nothing */
		    break;
		case 160:	/* 0=3=4=7 */
		    arb_mv(pts, gp, 1, 2, 6, 5, 0, 0, 0, 0);
		    break;
		case 672:	/* 2=3=7=6 */
		    arb_mv(pts, gp, 0, 1, 5, 4, 2, 2, 2, 2);
		    break;
		case 252:	/* 1=2=5=6 */
		    arb_mv(pts, gp, 0, 3, 7, 4, 1, 1, 1, 1);
		    break;
		case 60:	/* 0=1=5=4 */
		    arb_mv(pts, gp, 3, 2, 6, 7, 0, 0, 0, 0);
		    break;
		default:
		    (void) fprintf(stderr, "redoarb: bad arb5\n");
		    return 0;
	    }
	    break;
	    /* end of ARB5 case */
	case 4:
	    /* arb4 vectors:  0 1 2 0 4 4 4 4 */
	    j = svec[6];
	    if (svec[0] == 2)	j = svec[4];
	    arb_mv(pts, gp, uniq[0], uniq[1], svec[2], uniq[0], j, j, j, j);
	    break;
	default:
	    (void) fprintf(stderr,
			    "redoarb: unknown arb type (%d)\n", cgtype);
	    return 0;
    }
    return 1;
}

/*
 * Local Variables:
 * mode: C
 * tab-width: 8
 * indent-tabs-mode: t
 * c-file-style: "stroustrup"
 * End:
 * ex: shiftwidth=4 tabstop=8
 */
